A high proportion of NX-2 genotype strains are found among Fusarium graminearum isolates from northeastern New York State

Abstract

Fusarium graminearum, a fungal pathogen of wheat, barley, and corn, produces a variety of trichothecene mycotoxins that are important as virulence factors and as seed contaminants reducing grain quality. A previous survey of the pathogen in New York State identified variation in genes indicative of trichothecene diversity. Recently F. graminearum strains that produce a newly characterized trichothecene mycotoxin called NX-2 have been identified in North America. Using a large collection of F. graminearum strains from Willsboro NY, we found that the frequency of NX-2 genotype strains was 7–14 times higher than at other locations where it was reported previously. NX-2 genotypes were not only found in wheat heads but also found in high frequency from air samples and on maize ears and stubble. Because NX-2 genotypes may represent as much as 20% of the total F. graminearum population, this regional fungal population provides an opportunity to assess the effects of the novel NX-2 trichothecene on fungal virulence, toxin loading, and patterns of host specificity that could inform future disease management and plant breeding.